Starting apparatus for diesel engines



July 21, 1942. w. LEHMANN STARTING APPARATUS FOR DIESEL ENGINES 2 Sheets-Sheet l Filed June 25, 1940 u u I n Il .m IW. l i U MII w All wknmr o Ml I :VIII w v J 8. 2 .DI u

Jnventor' W/z y L WMA/wv,

/nramvfys July 21, 1942. I w. LEHMANN 2,290,646

STARTING APPARATUS FOR DIESEL ENGINES Filed June 25, 194() 2 Sheets-Sheet 2 Jnventqr: w/u. y 1 EHMA /v/v,

Patentecl July 21, 1942 STARTING APPARATUS FOR DIESEL ENGINES willy Lehmann, couhs, Germany, assigner to i "Famo Fahrzeug-und-Motorenwerke, G. m. b. H., Breslau, Germany, a corporation of Germany Application June 25, 1940, Serial No. 342,397 In Germany June23, 1939 6 Claims. (Cl. 12S-32) This invention is directed to a starting apparatus for an internal combustion engine of the Diesel type. More particularly the invention is directed to a starting mechanism in which the Diesel engine is started as an ordinary gasoline internal combustion engine, and after starting, switched over to operation on relatively heavy fuel oil.

In one well-known construction for starting Diesel engines, a cylinder head is provided which includes an auxiliary combustion chamber which Acooperates with the main combustion chamber in receiving an air-fuel mixture, the fuel being one of the lighter petroleum products such as gaso'- 'Y line or benzene, and an ignition device such as a spark plug by means of which the Diesel engine is started as an ordinary gasoline engine. After the engine has been started and brought up to a desired speed, the auxiliary combustion chamber is closed oi, and relatively heavy fuel oil injected into the main combustion chamber whereby the engine operates according to the convent tional Diesel engine. Inthis known construction, separate conduits for the gasoline-air mixture used for starting, and the air supply for the Diesel operation, have been joined externally of the cylinder head and then connected to a bore in the cylinder head leading to the combustion chamber. Each conduit is tted with a valve,

- and the two valves are interconnected so that when one conduit is open the other conduit becomes automatically closed.v

Difliculties arise inthe operation of the engine after the engine has been accelerated as `agaso line engine to the speed necessary for Dieseloperation, and the engine is beginning to operate as a Diesel engine. Diliiculty of igniting the Diesel fuel charge is encountered, and it has -been discovered that this diiculty is due to the fact that` gasoline or benzene used for the starting of the engine has precipitated in the relatively long passageway between the outside of the cylinder head and the inlet to the combustion chamber, and this condensed gasoline is carried along into the engine with the air supply for the Diesel operation. Hitherto known attempts to secure proper ignition of the heavy fuel oil at the moment the engine is changed from gasoline toDiesel opera# tion have not lbeen successful.

It is an object of this invention to provide a structure in which the engine can be smoothly operated as a Diesel engine immediately after being changed from gasoline to Diesel operation.

Another object ofthe invention is to provide a Diesel engine structure in which the presence of light fuel products used forstarting the engine is substantially eliminated from the air supply duct to the engine for Diesel operation.

A further object of the invention is to provide a cylinder'head construction fora Diesel engine which includes an auxiliary combustion chamber for starting pur-Doses, which head is light and compact in structure, and includes means for maintaining the eiective length of the bore, through which both the gasoline-air mixture for starting and the air used for running the Diesel engine are'carried, as small as possible. t

Another object of the invention is to construct a passageway in a cylinder head for a Diesel engine adapted to be started as a gasoline engine, so that a substantial part of the passageway in the head is composed of two passageways in a valve which has a simple and readily accessible construction. y

Generally these objects of the invention are obtained by including in the passageway within the cylinder head through which the gasoline-air mixture used for starting and the Iair used for running Diesel engine, are. both carried, a slide valve which in itself alternately forms substantially the whole of the passageway eitheri'or the air or for the gasoline-air fuel mixture. Accordinsly, the fixed bore of the prior art is in essence substantially replaced by one passageway for the chamber, the slide valve is automatically positioned to'feed gasoline-air fuel to the combustion chamber, while when'the auxiliary combustion chamberis cut oi, the slide valve is automatically moved tosupply air alone to the combustionchamber.

.The means by which the objects of the invention are obtained are more fully disclosed with reference to the accompanying drawings in which Fig. 1 is a cross-sectional view of the head of a Diesel engine disclosing the novel construction of this invention, and Fig. 2 is a similar view but showing the elements in a. different operating position.

In both Figs. 1 and 2 similar reference characters refer to similar parts. 'I'he engine block 2 contains the usual cylinder lining 4 in 'which a, piston 'operates. The portion S of the cylinder above piston 6 constitutes the main combustion chamber. The cylinder head 8 is provided with an auxiliary combustion chamber I0 into which a spark plug l2 projects-it being understood-that this chamber functiesfin the manner of an Otto engine, as' an` auxiliary combustion chamber for purposes of starting the Diesel engine. Chamber Il communicates with main combustion chamber l through a valve Il normally urged into seated position by spring I6 connected to valve stem II. In 1 the valve is shownheld in open unseated position so that auxiliaiy chamber Il communicates with main combustion chamber I for starting purposes.

To establish such communication, a rocker arm 2l is mounted on a shaft 22 journaled externally upon the cylinder head I. One end of this arm.

is urged downwardly by spring 24, while the other end of the arm is movable by cam 26 mounted upon shaft 2l turnable by wheel 3l.

A second arm 32 is xed at one end to shaft 22 and turnable therewith. A roller 34 is joined to shaft 32 andcontacts the end of stem I8 of valve Il. Consequently. turning of the wheel 30 causes a movement of arm 20 byrreason of cam sageway, any gasoline drops which have .collected therein are not carried along by air passing through port 44 into the combustion engine, and

Y consequently no diiiiculty is encountered in the 26 and spring 2l, and also a movement of arm 4'32. Movement of arm 32, of course, raises or lowers rollers -34 and'thereby moves valve I4 into open or closed position. i Joined to head 8 are conduit 36 adapted to supply a light oil fuel such as gasolineor' benzeneair mixture to the engine for starting purposes, and a second conduit 38 adapted to-supply air to the engine for the Diesel operation of the same on relatively heavyfuel oils. In prior known constructions these two conduits were connected externally of the cylinder. head to a common borewhich extended to the combustion chamber'.

In this invention, conduit- 36 *communicates through port III to a cylinder I2. Conduit 3B also communicates with cylinder l2 through port I4.

Cylinder 4I communicates through a relatively short passage II to a valve I8 through which entrance is made into main combustion chamber 5. Wall 5l separates the auxiliary combustion chamber Il from this .passageway 46.

Mounted within cylinder 42 is a gas-tight slide valve 52. vIn the construction shown this valve is provided .with a bore 54' which is adapted in the position shown in- Fig. 1 to establish communication between port 4l and passage I6.- The length of valve 52 is such that when it is raised in the position shown in Fig. 2, communication between port Il and passage 46 is established, while port'll is closed olif.

The raising 'and lowering of valve i2 is accomplished simultaneously with the operation of valve Il, by employ-A ing a -pin and slot connection 5i between the upper end of the valve and the end of arm 32.-

It is clear'that when the engine is to be started and run on a light fuel mixture such as gasoline,

the wheel il' is rotated to the position shown in Fig. 1 so that valve I4 is opened and the auxiliary chamber Il becomes a part of V`combustion chamber i so that the engine can be operated as the ordinary gasoline internal .combustion engine. In this position the valve 52 has been depressed so that gasoline-air mixture fed through conduit -enters into combustion chamber 5 throughV passage 4l and valve.v

After the engine has been started, the wheel A 'n is rotated tu the position shown m Fig. 2 so that valve Il is closed,.thus closing off auxiliary second valve comprising a piston.; a bore extendshort passage through s aid bore while closing said position whereby both air and air-.fuel mixture initial operation of the engine on a relatively heavy fuel mixture. At the same time the ap,

paratus is of light weight and simple structure,

and easily accessible 'for purposes of adjustment and repair.

Having now described a means by which the vobjects of the invention are obtained, I claim:

l. In a Diesel type engine having an auxiliary ignition starting system, the improvement comprising an inlet valve in the cylinderhead of said engine, a passageway in said cylinder head communicating with said inlet valve, an air duct for Diesel operation of said engine in said cylinder J 2. In a Diesel type engine a's in claim l, said second valve comprising a piston valve including separated passageways for said air and said airfuel mixture, respectively.

3. In a Diesel type engine as in claim `1, said ing through said piston, and means for moving said piston so that said bore provides communication between said fuel-air duct and said passageway while said piston closes communication I between said air duct and said passageway.

4. In a. Diesel type engine as in claim l, an auxiliary combustion chamber, a cut-oir valve between said auxiliary chamber and the main combustion chamber of said engine, and means for simultaneously actuating said second valve 4and said cut-off valve to open said cut-off valve and place said air duct in communication with said passageway.

*5. In a Dieseltype engine having an' auxiliary ignition starting system, an intake valve for the main combustion chamber of said engine, a passageway in the cylinder head ofsaid engine extending from an air port to said valve, a cylinder intersecting said passagewayl adjacent said intake valve so as to leave a very short passage between said'cylinder and said intake valve, an

air-fuel port in said cylinder, and a piston valve having a bore therethrough movably mounted in said cylinder to open said passageway and close said air-fuel port in one position and 'to place said air-fuel port into communication with said passageway to 'said air portwhen in another have a common path through said cylinder head only through said' short passage adjacent saidl chamber Il, while at the sme time valve 52 is raised so that air 'is fed .through conduit 38 and passage ll into the combustion chamber.` .As bore Il no longer forms'a part of the pas- '6. In a Diesel type engine-as in claim 5, means for actuating said intakevalve both forv the airfuel starting and the .air only for normal operation of said engine. WILLY LEHMANN. 

